1. Technical Field of the Invention
The present invention relates generally to a waste processing and recovery system. More particularly, the invention relates to a system for processing waste expanded polystyrene (EPS), reclaiming a resin used to form the polystyrene, and recycling a chemical used to process the EPS.
2. Description of the Related Art
Expanded polystyrene foam, also called EPS foam, is used in large quantities for packing manufactured product such as electronic equipment and home appliances. The foam polystyrene is easily formable in a plurality of desired shapes, yet is clean, easy to use, and relatively inexpensive.
However, foam polystyrene has several deficiencies. First, it does not decompose in landfills which is a significant problem since it is used in such large quantities and typically thrown away by consumers. Second, the EPS burns at very high incineration temperatures producing a very strong and offensive odor. And, these high temperatures may be very harmful to the incinerator. With these inadequate environmental results, alternative solutions have been sought for replacement of the expanded polystyrene.
Pulp based materials such as paper and cardboard have been tried due to the high recovery rate of these materials. Pulp-based materials owe their shock-absorption characteristics to their corrugated shape however, this shape does not absorb shock with results comparable to expanded polystyrene. Thus large consumer products such as washer and dryer sets, refrigerators and ovens must be packaged with EPS.
In view of the deficiencies in known methods for processing expanded polystyrene (EPS) and apparatuses for said process, an apparatus and method are needed for processing waste EPS foam with an organic solvent such that resin can be reclaimed or recaptured for producing recycled EPS foam and the organic solvent recycled for further recycling of EPS foam into resin.
It is an object of the present invention to provide an apparatus for dissolving expanded polystyrene foam into a polystyrene waste solution.
It is a further object of the present invention to provide an apparatus for separating the waste solution into a resin and an organic solvent.
It is yet a further object of the present invention to provide an apparatus for use with an organic solution which dissolves the EPS foam and recycles the organic solution.
It is another object of the present invention to have a system for recapturing the resin used to form EPS foam.
It is still another object of the present invention to provide system which can dissolve large quantities of EPS foam.
Specifically, the present invention provides a system for dissolving and separating expanded polystyrene having a first tank with at least one applicator, a second tank having at least one weir and at least one filtration system in flow communication, the first tank and the second tank being in flow communication. The first tank maybe a hopper for bulk feeding expanded polystyrene (EPS) foam and reducing the polystyrene and organic solution, to a polystyrene waste solution. The at least one applicator provides recycled organic solution to the first tank in order to dissolve the EPS foam. The first tank may have a sloped floor biasing fluid flow toward a fluid outlet near a lower portion of the first tank. Within the first tank, the EPS foam is dissolved resulting in a waste product comprising a resin and an organic solution. The first tank may also comprise an agitator, such as an auger or the like therein to increase the dissolution of the EPS foam. Alternatively, a person may manually agitate the contents of the first tank by stirring the EPS foam and organic solution thereby increasing the contact therebetween and amount of agitation.
In flow communication with the fluid outlet is a strainer which inhibits garbage and the like from flowing from the first tank to the second tank. A flow communication path is provided between the first and second tank and the flow communication may be induced by gravity feed or, as shown in the instant embodiment, may be pumped. The flow communication path of the instant embodiment is a metal pipe and provides flow between the first tank, a first pump, and the second tank. The first pump provides a suction or negative pressure on a first tank side of the pump and a positive pressure on a second tank side of the pump such that the pump induces flow from the first tank to the second tank.
Within the second tank are a plurality of compartments in flow communication. However, in an alternative embodiment a plurality of tanks in flow communication may be used, each having one or more compartments. The second tank acts as a settlement tank or separator tank. In the instant embodiment, three settlement compartments are defined by the second tank, a filtration system, and a weir. The second settlement tank has a first compartment defined by the tank walls and a sealed filtration system where the waste solution, comprising resin and organic solvent, is pumped. The resin has a higher density than the organic solvent. The difference in specific gravities insures that the non-soluble organic solvent forms a layer above the heavier resin.
The filtration system within the second tank is defined by a plurality of porous shells. As exemplified in the instant invention, the shells may be a plurality of PVC pipes, each having a plurality of holes therein, mounted within at least one filter bank. The at least one filter bank is defined by a metal frame which is mounted within the second tank and is sealed to prevent flow of the waste solution around the filter system. Each of the PVC pipes has an open top so that a wick material, preferably polypropylene rope, may be packed therein. The polypropylene rope acts as a wick to pull the organic solvent through the plurality of holes and across the filter system and into a second settlement compartment.
The second settlement compartment is defined by the second tank, the filter system and seal, and a weir. As the organic solvent and some reduced quantity of resin wick through the filter system, they are deposited in the second settlement compartment. As in the first settlement compartment, the second compartment allows the resin and organic solvent to separate due to their different specific gravities and non-solubility. The weir extends upwardly from the tank a pre-selected distance such that the organic solvent layer formed above the resin flows there over into a third settlement compartment.
The third settlement compartment is defined by the tank and the weir and has substantially clean organic compound therein. A second pump is disposed above the third settlement compartment with a suction line extending therein. The suction line provides a flow communication path between the third settlement compartment and the second pump. On the positive pressure side of the pump, a flow communication path or pipe extends to the first tank and the applicator disposed therein. The applicator receives the recaptured organic solvent and sprays the solvent through a plurality of nozzles over the expanded polystyrene foam being placed in the first tank. Thus the process begins again.
All of the above outlined objectives are to be understood as exemplary only and many more objectives of the invention may be gleaned from the disclosure herein. Therefore, no limiting interpretation of the objectives noted is to be understood without further reading of the entire specification, claims, and drawings included herewith.